Backyard Aquaponics
A place to discuss aquaponics

Is Vortex filter worth your 2 cents ?
Before I answer the above question, we have to evaluate the performance of the filter versus its cost. Can a vortex filter traps debris and fish pooh effectively ? It definitely can trap solids and garden debris such as leaves, which sink. Fish pooh ? You have to tell me !
When a fish discharge, we see a cloud of pooh coming from the anus of the fish. Have you observe how long it takes for the pooh to eventually all settle to the pond floor. A portion of it quite fast, a portion seemed never settles. If you intend to trap a portion of fish pooh that can settle, first you must measure the terminal velocity of the fish pooh. That is to measure the downward falling velocity of the fish pooh. I have never tried it but I guess we could put a couple of fish into a clean fibre tank to collect some pooh. Then drop the pooh into a meter high glass cylinder column of water. By timing the fall of the pooh one can measure the terminal velocity of the pooh. Terminal velocity means the steady state of falling velocity. When the pooh is first dropped it would fall quickly but after about 30 cm or so it should reach a steady speed. This is called the terminal velocity. With this measurement you probably would have some idea of what is the proportion of fish pooh you think you can trap with vortex filter.
Next, we have to calculate what is the uplift water velocity of the vortex filter. Water is piped in at mid level of the vortex tank. The column of water is being push upwards to be discharged at the top of the tank. To calculate the upward velocity of water column we divide the pond water turn over rate by the cross sectional area of the vortex tank.
After the dirt particles is drawn inside the vortex it has to settle by gravity. All particles which has a terminal velocity larger than the uplift velocity of water could settle. The rest of the particles would be discharged to the second vortex filter in series. For this reason many system fails to trap solids in the first settlement tank because the uplift velocity of water is high. To improve the efficiency we can have multiple settlement vortex tank mounted in parallel. If we have 3 series of tank in parallel we reduce the uplift velocity of water by 3 times.
In comparison to the conventional in ground settlement chamber, the vortex chamber is not able to do more than the law of physics dictates.
For conventional in ground settlement chamber the same law applies, i.e. the terminal velocity of the particles must be greater than the uplift velocity of water in the chamber otherwise particles would not settle. The reason we build a large settlement chamber is to achieve a low water uplift velocity to improve settlement. The law of physics dictates if the total cross sectional areas of the vortex settlement equals to the cross sectional areas of the in ground settlement chamber. Both will perform with equal efficiency.
The second chamber of vortex filter will be filled with Japanese mat. Which only means the water will not rotate or the most only the portion of water below the water inlet pipe rotate. Would the second chamber of vortex filter be more efficient than the second chamber of the in ground filter? The same law is at work here, it depends on the uplift velocity of the chamber. Rotation of the water inside the vortex chamber only works to migrate the dirt particles toward the center of drum. If your in ground chamber had a steep conical base, the dirt would also works its way down towards the discharge pipe.
In conclusion, if the vortex filter is having the same cross sectional area as the in ground filter, they should perform the same provided all things being equal. The choice of equipment one chooses would be decided by its operational ease and availability rather than by its performance.